The goal of this project is to provide a synthetic biomaterial capable of giving long-term repair of full-thickness chondral lesions with the aim of helping to reduce the 600,000 joint replacements carried out each year in the USA. Our company has developed a synthetic biomaterial technology with proven biocompatibility in treating over 33,000 patients for bone repair. This highly biocompatible technology is designed to provide an in situ organized environment for the regeneration of new tissue and has recently been shown to provide excellent repair in a pre- clinical osteochondral model. In this study, the regenerate tissue not only repaired the subchondral bone but also produced well-integrated hyaline cartilage and re-established the tide-mark zone. Building on the preliminary results from the pre-clinical osteochondral study and our patent protected position on the material's use with microfracture, Phase I of this proposal seeks initially to establish proper surgical method for implantation of the biomaterial in lesions with sizes spanning those normally treated by microfracture (1 to 4cm2). An ovine model is chosen to conform to preferences expressed by the FDA. Having established proper fixation technique in Phase I, the Phase II of the proposal derives data for use in a pre-clinical safety and efficacy study. Data from this accepted ovine model will form the basis of approach to the FDA to obtain an investigational device exemption (IDE) necessary to enter human clinical trials to support Pre-Market Authorization (PMA) for the commercial product. This treatment modality represents a safe, cost-effective long-term solution to an increasing patient population.